Bus bar mounting clip



April 5, 1966 c. A. BARNEY ETAL 3,245,031

BUS BAR MOUNTING CLIP Original Filed Nov. 2,' 1962 FIGZ FIG!

A? h .IIIIM J United States Patent 3,245,031 BUS BAR MOUNTING CLIPCharles A. Barney, Stow, and John Collins, Framingham,

Mass, assignors to Ark-Les Switch Corporation,

Water-town, Mass, a corporation of Massachusetts Continuation ofapplication Ser. No. 235,031, Nov. 2,

1962. This application Sept. 3, 1964, Ser. No. 394,226 4 Claims. (Cl.339-258) This invention is a continuation of our application Serial No.235,031 filed November 2, 1962, and now abandoned and relates to anelectrical connector using pressure and friction, such connectors beingused as clips for mounting bus bars and for connecting terminals ofelectrical devices thereto. More particularly this clip is adapted forthe mounting of cylindrical or round bus bars, rods, or wires, eithersolid or hollow, and is particularly useful with a series of switches orsuch electrical devices which must be connected by or to such bus bars,the clip being attached to a terminal of the switch or device andfurther providing a friction contact element extending at an angle tothe bus bar for making electrical connection to terminals of other wiresor devices by means of an opposite matching cooperating friction contactelement. Such clips thereby serve to connect lead wires to and fromappropriate bus bars and to connect bus bars to and from electricallyoperated accessories or devices.

One object of the invention is to provide a clip of the type describedabove which is simple and economical to manufacture and which is usefulin making connections to and from round bus bars without the use oftools. Another object is to provide in such a clip a high contactpressure over a comparatively large surface area so that the frictionalpressure contact interfaces of the bus bar and clip exhibit a lowresistance to current flow and the joint does not heat unduly. A furtherobject is to provide a bus bar connection clip which strongly resistsremoval of the bus bar or rod therefrom in a transverse direction whenonce applied but which permits longitudinal and rotary adjustment of therod with respect to the clip. A still further object is to provide a busbar clip carrying an extending friction contact reinforced againstmisalignment after connection of a bus bar thereto.

Other objects, advantages and details of that which is believed to benovel and included in this invention will be clear from the followingdescription and claims taken with the accompanying drawing in which areillustrated two examples of bus ba-r mounting clips embodying thepresent invention.

In the drawings:

'FIG. 1 is an enlarged perspective view of an exemplary clip shown apartfrom a bus bar and other elements to which it might be connected;

FIG. 2 is a side elevational view of the clip of FIG. 1 showing how acylindrical bus bar is held therein;

FIG. 3 is an enlarged perspective view like FIG. 1 but showing amodified form of clip according to the invention, and

FIG. 4 is a perspective view on a smaller scale showing a pair ofswitches or other electrical devices provided with clips according tothis invention, with round bus bars or rods secured in the clips toconnect terminals of the electrical devices to each other.

In carrying out the objects of this invention, in a preferred embodimentthereof the clip is made from a relatively thin flat sheet or strip ofresilient conductive metal, such as phosphor bronze, blanked or piercedinto a single piece which is thereafter bent up or similarly formed intoproper final shape. The single piece from which the clip is fabricatedis generally elongated, that is, its length is considerably greater thanits width, and a 3,245,031 Patented Apr. 5, 1966 portion of the piecenear the center will be left flat so as to function as a planar wall orbase 10 for the clip.

At one end of the base the piece is bent at a right angle to form acontact arm portion '12 projecting suificiently away from or beyond thebase wall so that a free connector contact area 14 is provided beyondthe diameter of a bus bar or rod B for which the particular clip isdesigned. Because the flat arm 12 and its contact area 14 are intendedto serve as parts of a frictional contact stab element extending atright angles to the axis of the bus bar in a plane parallel to the barand cooperating with a removable friction connector element or terminalsocket, the extended outer end of the arm 12 is bent or folded back uponitself as at 16 and a reinforcing or stiffening element portion 18 isprovided, backing up the arm 12, this stiffening element portionmaterially reducing the normal flexibility and resiliency of theprojecting stab portion of the clip. Because of the stiffening thusprovided, the arm 12 will not be bent out of proper position when a busbar is inserted in the clip.

At the end of the portion 18 near the base 10 a projecting clip mountingor connection tab 20 may be formed as shown, provided with a mountinghole 22 for the reception of a screw, rivet, or similar clip-holdingelement in a manner and for purposes readily understood. If desired, thebase portion 10 itself might be provided with such a mounting hole, iflocated in a place such that the clip-holding element used therein doesnot interfere with proper'contact of a bus bar within the clip andagainst the base portion and the contact arm.

Opposite the stiffened contact arm and at the other end of the baseportion, the resilient metal strip is bent at a right angle to the baseto form a spring arm portion 24 generally parallel to and opposite thearm 12, this arm also projecting from the base substantially beyond thediameter of a rod which is to be held in the clip. At the upper end ofthis spring arm the piece is bent downwardly again or back toward thebase portion and toward the contact arm as at 26, this bend being made,as shown, preferably at an angle of about twenty degrees with respect tothe arm 24 and facing arm 12 at a low angle to form a second spring armportion 28 ending in an arcuate contact wall portion 30 above the base,of a curvature matching a segment of the circumference of a rod to beheld in the clip. The concave curved wall faces both the base 10 andcontact arm 12, or the junction between base 10 and arm 12. Before a busbar or rod B is con nected to the clip, as shown in FIG. 2 the slantedspring arm 28 will be in the position shown in dotted lines. As a bar isforced into the V-opening between the contact arm 12 and the facingslanted spring arm 28 it forces the spring arms 24 and 28 to flex untilthe bar passes below the bend 32 between the arm 28 and the arcuate wall30. The lower free end of curved contact wall 30 being further from wall12 than the bend 32, as the bar passes the bend the spring arm 28 andthe first spring arm 24 force and snap the arcuate wall 30 resilientlyinto contact with the bus bar, pressing the bar into line contact withthe base 10 as at 34 and into line contact with the arm 12 as at 36.

The material of the clip is so selected and the dimensions of thevarious portions of the clip are so designed that an extremely highcontact pressure is maintained between the clip and a cylindrical bar ofa diameter for which the clip is designed. The stiffening of arm 12prevents its being forced out of line when a bus bar is forced into theclip. As should be obvious from the above description, the bus bar hasthree contact areas with the clip, the line contact 34, the line contact36, and the arcuate contact surface area of the curved wall 30. Thismultiplicity of contact positions, spaced around the bus 3 bar, underhigh pressure according to properly selected materials and dimensions,insures that the interfaces between the bus bar and the clip will notheat unduly there being the minimum of resistance to current flow withsuch conditions.

Note also that the arcuate contact Wall 30 faces and engages thecircumference of a bus bar in the clip at points above or beyond thelevel of the line contact 36 and outside of the line contact 34 so thatthe bar is always pressed not only sidewise against the line 36 but alsoinwardly against the line 34 on the base. This positioning of the partsmeans that although the bar may be introduced into the clip relativelyeasily in a transverse direction because of the low slope of arm 28relative to arm 12, it is difficult to remove the bar in the reversedirection, this being resisted by the high angle of the contact wall 30and engagement of the bend 32 above or beyond an imaginary line passingthrough the contact line 36 parallel to the plane of the base 10.However, there is nothing excepting friction and spring pressure betweenthe bar and the clip to prevent relative shifting between the bar andthe clip in a direction axially or rotationally of the bar. Thus, evenafter a round bar is fully engaged in the clip, adjustment of the barand the clip relative to each other may be made in the axial directionor by rotating. Such adjustments facilitate the final mounting ofdevices carrying the bus bar clips even after bars are connected to theclips.

The form of the invention illustrated in FIG. 3 contains all of theessential elements described above in connection with FIG. 1, includingthe base portion the stiffened contact arm portion 12, the spring armportions 24 and 28, and the arcuate contact wall portion 30. However,whereas the stiffened contact arm 12 in FIG. 1 is intended as a malestab or friction contact blade for cooperation with a matching femalereceptacle or socket, the form of FIG. 3 provides the contact arm 12with formations to produce a female receptacle or friction contactsocket at a right angle to the axis of the bar with surfaces for makingremovable electrical connection to an opposite matching contact blade orstab in a plane parallel to the length of the bar. This is done byextending the side edges of the contact arm 12 in FIG. 3, bending orfolding these integral side wings 19 back toward arm 12 to form betweenthem and the arm a socket 21 with internal surfaces adapted for thereception of a cooperating male stab or friction contact blade whichmight be secured to the end of a wire, connector, or electricalaccessory or device. In this form of the invention as in the form ofFIG. 1 a clip mounting or connection tab (not shown) may be provided byan integral extension from an end of one or both of the folded over sidewings 19 or otherwise on the stiffened contact arm 12. As describedabove, and if desired, the form of clip in FIG. 3 might be provided witha mounting hole in the base. The folded side Wings 19', like the foldedreinforcing element portion 18 of the first form, serve to stiffen orreinforce the contact arm 12 so that its inner surface will furnish astable area for a line contact as between the clip and an inserted busbar, and

so that the arm may function as a part of a frictional contact elementwithout being forced out of line.

One manner of use of clips according to this invention is illustrated inFIG. 4 in which switches or other electrical devices or appliances 40are provided with male connector members or tongues 42 which projecttherefrom and form electrical terminals. Certain of these terminals areintended to be connected to bus bars B common to several switches, andthese terminals are provided with clips according to this invention,each including a relatively rigid contact arm 12, spring arms 24- and 23and contact wall 30. The base 10 of each clip is connected mechanicallyand electrically either through a mounting tab 2% or by other means toelectrical terminals or elements in the switch as should be clear fromthe preceding description. The contact arms 12 may be connectedremovably to cooperating frictionally engageable contact elements on theends of lead Wires or in fixed receptacles as desired so that a wideselection or choice of possible connections of the switch terminals tovarious bus bars and circuits or appliances is possible. When thecontact arms 12 are in the form of male stab or blade elements as shownin FIGS. 1, 2 and 4, they may be provided if desired with dimples ordepressions 44 for engagement with corresponding projecting bosses incooperating friction contact receptacles or sockets in a manner known tothe art.

As will be evident from the foregoing description, certain aspects ofthis invention are not limited to the particular details set forth asexamples, and it is contemplated that various and other modificationsand applications of the invention will occur to those skilled in theart. It is therefore intended that the appended claims shall cover suchmodifications and applications as do not depart from the true spirit andscope of the invention.

What is claimed as new and is desired to be secured by Letters Patent ofthe United States is:

1. A resilient metal mounting clip for a cylindrical bus bar of a givendiameter providing a friction contact element extending fromysa'id barcomprising,

a central base wall portion,

a friction contact arm on one end of said base, at an angle thereto,extending away from the base substantially beyond the given diameter ofa bus bar to be received in'the clip,

a first spring arm portion integral with the other end of said base,bent at an angle thereto, extending away from the base opposite saidcontact arm,

a second spring arm portion at the end of said first spring arm portionbent at an acute angle thereto, extending in a direction back towardsaid base and slanted toward said contact arm, and

an arcuate contact wall portion at the end of said second spring arm,said arcuate wall being of a curvature matching a segment of thecircumference of a bus bar to be received in the clip.

2. A mounting clip for a cylindrical bus bar of a given diameterproviding a friction contact element extending from said bar comprising,

a single elongated strip of resilient metal formed into a central planarbase wall portion,

a contact arm portion integral with one end of said base, bent at anangle thereto, extending away from the base substantially beyond thegiven diameter ofa bus bar to be received in the clip,

a reinforcing portion extending integrally from said contact arm, foldedback toward the arm to stiffen said arm and complete a friction contactelement on the clip,

a first spring arm portion integral with the other end of said base,bent at an angle thereto, extending away from the base opposite saidreinforced contact arm,

a second spring arm portion at the end of said first spring arm portionbent at an acute angle thereto, extending in a direction back towardsaid base and slanted toward said contact arm, and

an arcuate contact wall portion at the end of said second spring arm,said arcuate wall being of a curvature matching a segment of thecircumference of a bus bar to be received in the clip.

3. A clip for mounting a cylindrical bus bar of a given diameter and forproviding a friction contact stab extending at a right angle to the axisof said bar comprising,

a single elongated strip of resilient metal formed into a central planarbase wall portion,

a contact arm portion integral with one end of said base, bent at aright angle thereto, extending substantially beyond the given diameterof a bus bar to be received in the clip,

a portion extending integrally from the end of said contact arm, foldedback against the arm to reinforce and stiffen said arm and complete afriction contact stab on the clip,

first spring arm portion integral with the other end of said base, bentat a right angle thereto, extending first spring arm portion integralwith the other end of said base, bent at a right angle thereto,extending opposite said contact arm beyond the given diameter of a busbar to be received in the clip,

opposite said reinforced contact arm beyond the given 5 second springarm portion at the end of said first diameter of a bus bar to bereceived in the clip, spring arm bent an an angle of the order of aboutSecond spring arm portion at the end of said firs twenty degreesthereto, extending in a direction back spring arm portion bent at anangle of the order of toward said base and said con tact arm, and

twenty degrees thereto, extending in a direction back a curved concavewall portion at the end of said sectoward said base and said contactarm, and 10 and spring arm portion, said curved wall facing the junctionbetween said base wall and said contact arm portions and being of acurvature to engage a bus bar to be received in the clip,

whereby said spring arm is adapted resiliently to press said curved wallagainst a bus bar in the clip and urge the bus bar against both saidcontact arm and base wall.

a curved concave Wall portion at the end of said second spring arm, saidcurved wall facing the junction between said base wall and said contactarm portions and being of a curvature to engage a bus bar to be receivedin the clip, 5

whereby said spring arms are adapted resiliently to press said curvedwall against a bus bar in the clip and urge the bus bar against bothsaid contact arm and base wall.

4. A resilient metal clip for mounting a cylindrical bus 20 bar of agiven diameter and for providing a friction con- References Cited by theExaminer UNITED STATES PATENTS tact stab extending at a right angle tothe axis of said 7831061 2/190 Mills 339-257 bar Comprising 2,391,42812/ 194: Link 339258 X a central planar base wall portion 3,003,13210/1961 Johnson et al 339-258 a friction contact arm on one end of saidbase, at a right angle thereto, extending substantially beyond the givendiameter of a bus bar to be received in the clip,

25 JOSEPH D. SEERS, Primary Examiner.

I. H. MCGLYNN, Assistant Examiner.

1. A RESILIENT METAL MOUNTING CLIP FOR A CLYINDRICAL BUS BAR OF A GIVENDIAMETER PROVIDING A FRICTION CONTACT ELEMENT EXTENDING FROM SAID BARCOMPRISING, A CENTRAL BASE WALL PORTION, A FRICTION CONTACT ARM ON ONEEND OF SAID BASE, AT AN ANGLE THERETO, EXTENDING AWAY FROM THE BASESUBSTANTIALLY BEYOND THE GIVEN DIAMETER OF A BUS BAR TO BE RECEIVIED INTHE CLIP, A FIRST SPRING ARM PORTION INTEGRAL WITH THE OTHER END OF SAIDBASE, BENT AT AN ANGLE THERETO, EXTENDING AWAY FROM THE BASE OPPOSITESAID CONTACT ARM, A SECOND SPRING ARM PORTION AT THE END OF SAID FIRSTSPRING ARM PORTION BENT AT AN ACUTE ANGLE THERETO, EXTENDING IN ADIRECTION BACK TOWARD SAID BASE AND SLANTED TOWARD SAID CONTACT ARM, ANDAN ARCUATE CONTACT WALL PORTION AT THE END OF SAID SECOND SPRING ARM,SAID ARCUATE WALL BEING OF A CURVATURE MATCHING A SEGMENT OF THECIRCUMFERENCE OF A BUS BAR TO BE RECEIVED IN THE CLIP.